This invention relates to telecommunications systems, and more particularly to telecommunications systems having facilities for call, session, and/or transaction processing using subscriber or line characteristics stored in a location remote from the switching facility handling the call.
In recent years, telecommunications users have become both highly sophisticated service consumers and highly mobile. As a result, users desire the ability to take their telecommunications services with them wherever they go, and they desire that the user interface by which they access their services remain consistent at all times and in all locations.
In the years between the adoption of automated telephone switching and the wide application of stored-program telephone switching systems, telephone users within broad geographic regions experienced an extremely consistent user interface. Within the United States, for example, the procedures for making and receiving calls were consistent, so a person using a telephone away from home could expect to use the telephone in the same way, and could expect the telephone and telephone system to behave in the same ways, as at home. Telephone calling features were typically limited to placing calls by dialing a directory number and receiving calls by lifting the receiver when the telephone rang. Features which are now popular, such as xe2x80x9cCall Waitingxe2x80x9d, xe2x80x9cCall Forwardingxe2x80x9d, xe2x80x9cThree-Way Callingxe2x80x9d, xe2x80x9cCaller-IDxe2x80x9d, and the like, were not available.
At the same time, users understood that their telephone subscriptions (including any features and billing arrangements) were associated with their telephone xe2x80x9clinexe2x80x9d at a fixed location and did not expect access to that line or subscription when traveling. If access to telephone service was required while traveling, the traveler could use a pay telephone or could arrange with a host or hotel to make and receive calls using the host""s or hotel""s subscribed telephone service.
As telecommunications users have gained mobility and sophistication, users have desired that their subscribed telecommunications services be available wherever they may be located. Conventional public wireless telecommunications systems, including cellular and PCS wireless systems in North America and GSM wireless systems in Europe, have provided a partial but unsatisfactory solution. Conventional public wireless systems are not well integrated with private business communications systems, so that a user generally cannot use a public wireless terminal make and receive calls in the context of the private system. Such calls generally appear to originate from or terminate on the external public network. In addition, a wireless subscriber may carry a wireless terminal which can access services in a wide variety of locations, but access to service often depends on whether the subscriber""s xe2x80x9chomexe2x80x9d telecommunications service provider directly serves the traveling subscriber""s location, or whether the home provider has made a service arrangement with another provider that directly serves the location. Further, even when service providers offer network services that are marketed and billed consistently over wide geographic areas and for which no special charge is made for use away from a home system, the services are not necessarily provided by a homogeneous network infrastructure. Thus service and feature availability, and the user interface required to access these features, may differ from what is available to or experienced by the user when at the home or business location. Moreover, the xe2x80x9croamingxe2x80x9d features of wireless telecommunications systems have generally been limited to wireless services, which historically have not enjoyed the variety, scope, reliability, and bandwidth of modern land-line telecommunications services.
Historically, switched telecommunications systems, including both land-line and wireless systems, have associated information defining the services, features, billing treatment, and the like, which will be provided to a user, with a user""s telephone xe2x80x9clinexe2x80x9d or xe2x80x9csubscription.xe2x80x9d Land-line systems generally have permitted a user to access services via the line solely at the customer premises at which the line is terminated (with the possible exceptions of call-forwarding and arrangements to bill to the user""s own service calls made via a different line). Accordingly, the canonical information defining a user""s service or subscription has conventionally been stored in a database that resides on the telephone switching system that serves the user""s line, and is associated with that line. When calls are made to or from the user""s line, the switching system typically may consult the database to determine the services, features, and billing treatment to be provided on that line and processes the calls accordingly. However, these services, features, and billing treatment have not necessarily been portable from one switching system type to another, and even if a second switching system type superficially supports the features and services of a first, interactions between the features and services may vary greatly.
Wireless telecommunications systems also historically have defined a user""s service, feature, and billing treatment using database entries associated with a user""s subscription or line. Although wireless systems do not provide a physical line or port with which the user""s subscription is continually associated, the subscription (including services, features, and billing treatment) may be conceptually associated with a unique directory number or subscriber identifier and treated as a telephone line in a manner analogous to that of land-line systems. Conventional wireless systems typically store the database entries defining a user""s subscription in a switching system or a Home Location Register (HLR) associated with the user""s home wireless network. When a user accesses services remotely, some of the subscription information may be exported to the telecommunications switching system or a Visitor Location Register (VLR) serving the user""s location and may then be used to process and bill calls.
Although the aforementioned wireless systems provide users some capabilities to access services remotely, they are incomplete and unsatisfactory. First, the remote access capabilities of wireless systems have not, as yet, been extended to land-line systems. In particular, land-line systems do not provide means for a user to identify herself or himself (or the associated subscription) to a remote telecommunications system and request that all services and features to which the user subscribes on a home system be delivered via the remote system.
Second, even in the wireless domain, services, features, and the user interface provided to a user at the remote location may vary significantly from those provided when the user is served by the home system. Variations in access to service, user interface, and feature availability and performance arise from a number of factors. Telecommunications switching equipment is produced by several different vendors, and although most equipment used in public networks provides a consistent set of basic services, the capabilities for advanced features and services, and the implementation of such features and services, varies among vendors and particular equipment models. Moreover, there are many telecommunications service providers and telecommunications regulatory authorities, each of which may specify aspects of features, services, and user interface, which aspects may vary according to their marketing plans, customer requirements, or the desires of their regulatory constituency. A feature or service, and the associated user interface, furnished by a particular telecommunications service provider, in a particular location, using particular equipment and operating software, may be identical, subtly different, profoundly different, or entirely unavailable from a different provider, or in a different location, or using different equipment or operating software.
Thus, when a user accesses a telecommunications service at a remote location, even though their subscription information, as recorded in the database of their home switching system or telecommunications network, specifies that they receive a particular service or feature, the service or feature may be unavailable or may perform in a manner different from what the user expects.
Although it might appear that the aforementioned disadvantages of existing telecommunications systems might be easily resolved by having all vendors and service providers agree to provide a common set of features and services, that solution is unlikely to be successful in the near term. Absent contrary regulatory constraints, service providers and vendors have used, and continue to use, product differentiation as a primary marketing tool. Also, the installed base of telecommunications equipment represents an extremely large investment. Rapid, wholesale replacement of the infrastructure equipment would be unfeasible, and upgrading all existing equipment to a common set of features would be difficult and expensive. Moreover, existing system architectures would not necessarily permit all variations of existing features to be provided on all equipment. Further, even for advanced models of telecommunications equipment, it is often not practical to install all available features on any field application of the equipment. Each feature or service furnished on the equipment has a non-negligible cost, and consumes equipment resources (e.g., storage) from a limited pool. Because of the interrelationships between various features and services, the resources required for each feature and service, as conventionally implemented, may grow non-linearly with the number of features and services present.
Further, the new development and implementation of a large, common set of telecommunications features, harmonizing the capabilities of equipment from many vendors and the requirements of many service providers, using conventional architectures and tools, would be prohibitively expensive and time-consuming. The architecture and programming models of telecommunications equipment vary among vendors and equipment models. Databases describing subscriber and line characteristics, which are typically resident on each switching system, vary greatly in structure and interpretation. Thus, as conventionally implemented, existing telecommunications systems have not provided telecommunications users the desired ability to take their telecommunications services with them wherever they go, while maintaining a consistent user interface at all times and in all locations, and it is unlikely this goal could be timely and feasibly accomplished using current architectures.
It is therefore an object of the present invention to provide a telecommunications system which minimizes the aforementioned disadvantages of prior art systems.
A telecommunications system constructed according to the present invention includes at least one subscriber terminal, a serving telecommunications exchange, a serving exchange image store, and a home telecommunications agency, interconnected using suitable network facilities, as described further.
The subscriber terminal may be a wired telephone, a wireless telephone, a data terminal, or any other device for providing an interface enabling a user to access the telecommunications system. The subscriber terminal preferably has a facility for operatively coupling to a Portable Subscriber Module (PSM), which uniquely identifies the subscriber to the subscriber terminal and to the home agency. Optionally, the PSM may also store information relating to services or features to which the subscriber has subscribed, for use by the subscriber terminal or the serving telecommunications exchange. The PSM and subscriber terminal must be selected for compatibility. Preferably, the PSM and subscriber terminal may implement in common a standardized format or language for interchanging subscriber, service, and feature information.
The serving telecommunications exchange may be any device or system which provides network access and call, session, connection, packet, or datagram processing functions to a subscriber terminal. The term xe2x80x9cexchangexe2x80x9d as used herein is not intended to refer to a specific architecture, and in particular, does not imply the presence of a conventional fabric for switching time-multiplexed PCM voice channels arranged in time slots. Hereinafter, the serving telecommunications exchange will be referred to as a Stored Program Control Center (SPCC).
The home telecommunications agency is a repository for information and services relating to a subscriber""s subscription. The agency may include one or more individual agents which are responsible for maintaining information about subscriptions and for providing various subscription-related services to requesters. The agents may generally be implemented as software running on suitable network-connected general-purpose computing facilities, or other network elements, and may be referred to as xe2x80x9csoftware agentsxe2x80x9d. In accord with the present invention, there is described herein an exemplary embodiment thereof in the environment of a telecommunications network. One of skill in the art will appreciate that with minimal modifications the invention may be applied more generally to the field of information processing and related arts. Although the term xe2x80x9ctelecommunications agencyxe2x80x9d is used herein, the agency functions could also be fairly characterized as those of an xe2x80x9cinformation processing agency.xe2x80x9d Thus, the term xe2x80x9ctelecommunications agencyxe2x80x9d is also intended to incorporate an xe2x80x9cinformation processing agency.xe2x80x9d
The term xe2x80x9cimagexe2x80x9d is used herein to refer to the collection of information concerning a particular user or subscription needed by the serving SPCC to process a specific call, and may include subscription, service, feature, and billing information. The xe2x80x9cimagexe2x80x9d for a call may include references to or identification of specific services or features to be made available to the call. In some embodiments, the xe2x80x9cimagexe2x80x9d for a call may also include instructions, call processing steps, billing, authorization limits, or other indicia defining to the serving SPCC certain aspects of such services or features, such as CPE type, implementation, behavior, or performance.
The serving SPCC preferably has coupled thereto an image storage facility for storing temporarily images associated with calls being served by, about to be served by, or having recently been served by, the serving SPCC. The image for a call may be delivered to the serving exchange from the subscriber""s home telecommunications agency and/or from the subscriber""s Portable Subscriber Module responsive to instructions from the agency. A subscriber desiring to communicate through the telecommunications system must register or identify herself or himself to the serving exchange. The registration may occur upon subscriber request by inserting a PSM into a land-line or wireless subscriber terminal. Alternately, a subscriber may register by manually entering suitable identifying information via a subscriber terminal. The registration could also occur an automatic function of a subscriber terminal (as is now done in wireless systems), based on, for example, information contained in an embedded or removable PSM.
The registration information may directly identify the subscriber""s home telecommunications agency, or the serving SPCC may use the registration information to look up the user""s home agency in a local or network database. The registration information is transmitted to the user""s agency for verification and to allow the agency to determine how to direct the subscriber""s incoming calls.
In accord with an aspect of the present invention, the SPCC need not continuously retain, for each authorized or potential subscriber, the subscriber-related information which has been conventionally used to provide service to that subscriber. Such information may include, for example, information needed to authenticate the subscriber, information identifying equipment or resources assigned to the subscriber or the subscriber""s line, information for translating directory or routing numbers to line equipment numbers, vendor-proprietary tables indicating services or features to which the subscriber is entitled, and the like. Instead, the SPCC instantiates an image for each subscriber service when the subscriber registers or when service is requested. The image preferably contains all subscriber-related information needed by the SPCC to provide the requested service for the subscriber.
When the subscriber originates a call, the serving SPCC requests an image for that call from the subscriber""s home agency. The information comprising the image for the subscriber""s call may be transmitted by the home agency itself, or by the PSM in response to instructions from the home agency, or some combination of the two, to the serving SPCC""s image store, where the image resides until the call has concluded, after which the image may be erased.
Each serving SPCC need maintain in its image store only images for active, impending, or just-concluded calls. Accordingly, subscriber service images may be considered xe2x80x9ctransientxe2x80x9d in the sense that they are not intended to persist in the serving SPCC in the intervals between subscriber service instances. However, an agency, an agency gateway, or an SPCC may cache subscriber service images where appropriate, provided that cached copies of images which become stale are properly invalidated, as is known in the art. Each SPCC also must provide a minimum set of native or core features for initial operation. Because a new image is provided by the user""s agency with each call, service, or registration, problems with stale subscription information in serving SPCCs are minimized, and service, feature, and subscription changes may take effect as soon as the agency records them. Because fewer records need be maintained in the image store (compared to conventional systems which typically maintain some subscription information for a large plurality of users, only a tiny fraction of whom are actively involved in a call at any time), the information in each image may be highly detailed, allowing a serving exchange to identically replicate for each of a large plurality of users the services, features, billing treatment, user interface, and interactions among these elements such users would receive or experience from their home telecommunications network.
In accord with a further aspect of the invention, a subscriber service image may include instructions, call processing steps, or other indicia defining to the serving exchange the implementation, behavior, or performance of one, several, or all services, features, billing treatment, or user interfaces to be available in connection with the call. Moreover, the information comprising the image may be distributed among the subscriber""s home agency and the subscriber""s PSM, and such information may be transmitted to the SPCC from either or both of the home agency and the PSM. Thus, certain features or services to which a subscriber has subscribed may be provided as a core function of an SPCC, while others may be defined by image information supplied from the home agency and/or PSM. This advantageously eliminates the need to maintain in each SPCC software defining all possible services and features that might be required by all possible subscribers, many of whom may never or only rarely require service at the SPCC. Preferably, feature and service identification, and the instructions, call processing steps, and other indicia needed to define a feature or service, may be provided using a standardized protocol, so that SPCCs and agencies may easily determine whether a service or feature is natively provided by the SPCC or must be supplied as part of the subscriber service image.
In accord with a further aspect of the invention, certain features or services which may be requested from a serving SPCC but which cannot be provided by that SPCC may be provided by another SPCC, such as one in the subscriber""s home network. This may occur if a serving SPCC lacks suitable equipment, facilities, or other resources to provide the requested feature or service. For example, a subscriber may request a conference call involving a large number of parties, which call may require special conference bridge circuits for which the serving SPCC is not equipped. In such situations, the subscriber""s home agency instructs the serving SPCC to extend the call to another SPCC which is equipped to provide the requested service.
In accord with a further aspect of the invention, the home agency maintains a database of service subscriptions for the subscriber and synchronizes the contents of the subscriber""s PSM accordingly. The Home Agency, responsive to service change transactions from a service provider""s service order entry, provisioning, and business support systems, transmits PSM update instructions to a subscriber terminal at which the subscriber has registered.